Recycle installations

It has been suggested by producers of brominated flame retardants that the health risks related to the extrusion of plastics containing PBB and PBDE could be avoided by strengthened worker protection measures In the recycling installations. As an example It was recommended that workers carry protection masks. Clearly, the substitution of the concerned substances would provide the best protection of the concerned workers." European Parliament and Council, 2002. 

General Considerations Molecular Separation Microseparation Macroseparation Recycle Installations Grinding Air Flotation Washing Equipment References... 

Maximise asset recovery/recycle installation Unique hardware/software... 

The impact of the regulations in Table 4 is to require users and producers of VOC ketones to limit release by either reformulating to new solvent systems, to install environmental control systems which recover and recycle solvents, or reduce emissions with carbon absorption beds or incineration equipment. The use of some individual ketones will decline further, but the overall short-term use of ketones is forecast to remain stable (10). 

N2, and traces of PH, CO2, E, and S large furnaces generate off-gas at a rate of about 120—180 m /min. In most installations the off-gas is passed through a series of Cottrell electrostatic precipitators which remove 80—95% of the dust particles. The precipitators ate operated at temperatures above the 180°C dew point of the phosphoms. The collected dust is either handled as a water slurry or treated dry. Einal disposal is to a landfill or the dust is partially recycled back to the process. The phosphoms is typically condensed in closed spray towers that maintain spray water temperatures between 20 and 60°C. The condensed product along with the accompanying spray water is processed in sumps where the water is separated and recycled to the spray condenser, and the phosphoms and impurities ate settled for subsequent purification. 

The benzene—toluene fraction is further fractionated in a small column, not shown in Figure 5, to recover benzene for recycle to the alkylation unit and toluene for sale. This toluene can be converted to benzene by hydrodealkylation but the high selectivity catalyst has reduced the formation of toluene in the dehydrogenation reactor to the point where the cost of installing a hydrodealkylation unit is difficult to justify even in a large styrene plant. 

Modification of Equipment. (/) Install equipment that produces minimal or no waste. 2) Modify equipment to enhance recovery or recycling options. (I) Redesign equipment or production lines to produce less waste. (4) Improve operating efficiency of equipment. (5) Maintain strict preventive maintenance program. 

Recycling and Reuse. (/) Install closed-loop systems. 2) Recycle on site for reuse. 3) Recycle off site for reuse. (4) Exchange wastes. 

Any type of sohds conveyor may be suitable for recycle mixing however, the most universally applicable is the double-shaft pug-miU-type paddle mixer. This conveyor or mixer should be insulated to prevent excessive heat losses from the hot, dry recycle product. To ensure uniformity in the recycle operation, a surge storage reserve of recycle sohds should be installed for startup purposes and in the event of interruption of product discharge from the cyhnder. In recycle operations, 50 to 60 percent product recirculation is found economical in many instances. 

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